Adequate selection of material constituents and test methods are necessary for workability specifications and performance of hardened concrete. An experimental program was performed to evaluate the suitability of various test methods for workability assessment and to propose performance specifications of prestressed concrete. In total, 33 self-consolidating concrete (SCC) mixtures made with var...

In this article a distinction between a pragmatic and a critical orientation of action research is made. These orientations can be considered, implicitly or explicitly, to be the main alternatives in AR today. What are the assumptions behind, and practical implications for, AR projects with different orientations? A number of themes are introduced where a tension between the two are identified ...

Experiences in the development of Ultra High Performance Concrete found a very high flowability in concrete with low water powder ratio. Because of the high viscosity of the cement paste, compaction was necessary. To improve the compaction characteristics of the concrete the idea of adding coarse aggregate was developed. The first tests showed a good workability of the fresh concrete and a good...

The effect of alkali content (% K2O + %Na2O) on the mechanical properties of alkali activated blast furnace paste has been investigated. The paper presents the study on workability, compressive strength, split tensile strength and microstructure of alkali activated blast furnace slag paste specimens prepared by using of sodium silicate and potassium hydroxide solution as activators. The experim...

The quality of the refractories applied on integrated gasification combined cycle should be a key factor that affects both the reliability and the economics of gasifier operation. To enhance the workability of chromia/alumina castables, three types of ultrafine alumina powder were added to improve the workability. Densification behavior of such castables in the presence of ultrafine alumina was...

There is a worldwide interest in using fibers of different types in concrete mixtures. In this regard, as the use of PET fibers has gradually increased during the last decade, this study aims to investigate the effects of PET fibers on the mechanical properties of hardened concrete and the workability of fresh concrete. To this end, different contents of PET fibers (PC= %0, %0.5, %1 and %1.5) a...

superior performances of self-compacting concrete (scc) in fresh state to achieve a more uniform distribution encourage the addition of fibers in concrete which is a motivation for structural application of fiberreinforced concrete. fiber addition reduces the workability of self-compacting fiber reinforced concrete (scfrc). to provide required workability of the scfrc, more paste is needed in t...